A large number of designs of plastic rings are known in the prior an for hanging curtains and shower curtains. These are illustrated in the following patents:
Blod, U.S. Pat. Des. No. 178,862 shows an open circular curtain ring with a connecting pin that bridges the edges of the gap.
Imershein, U.S. Pat. Des. No. 228,624 illustrates a design of a shower curtain holder with a snap connector. However, the pin forming the snap connection is not slotted at the end.
Bussell, U.S. Pat. Des. No. 296,299 shows a ring that is substantially circular with a gap bridging pin.
Bussell, U.S. Pat. Des. No. 296,299 shows a ring that is a substantially square curtain holder with a circular hole, and a pin that bridges the gap.
Snyder U.S. Pat. No. 3,115,181 describes a curtain ting construction which is rather complex and difficult to manufacture.
Kimel, U.S. Pat. No. 3,772,734 describes an openable ring for curtains having a body in the form of a loop carrying two jaws at the end of the loop.
Thus, known shower curtain rings may constitute a loop designed in such a manner as to "click lock". Due to the design of these or their complexity they often can only be produced at low speed and in limited quantities.